David Attenborough with a leatherback turtle in a special episode of "Planet Earth: Blue Planet II" on BBC America. (Gavin Thurston / BBC America)

SERIES

The Zoo: Bronx Tales The Bronx Zoo staff makes the journey to east Africa to return to the wild thousands of toads it helped rescue from extinction in the season premiere of the unscripted series. 8 p.m. Animal Planet

Saturday Night Live Sterling K. Brown becomes a first-time host, and singer-songwriter James Bay does his first "SNL" performance. 8:29 and 11:29 p.m. NBC

Ghost Adventures Zak Bagans and Aaron Goodwin return to San Jose to reopen their investigation of the Winchester Mystery House in this new episode. 9 p.m. Travel

Falling Water In the season finale, Taka and Alex (Will Yun Lee, Sepideh Moafi) interrogate Shadowman (Dru Viergever), while Tess (Lizzie Brochere) learns that her mother had a history with Taylor Bennett's (Mary McCormack) buyer. David Ajala and Kai Lennox also star. 10 p.m. USA

MOVIES

My Cousin Rachel Writer-director Roger Michell's 2017 adaptation of Daphne Du Maurier's mystery novel stars Rachel Weisz as Rachel Ashley, an enigmatic beauty who may or may not have killed her late husband. The dead man's cousin (Sam Claflin) is almost certain she's guilty, yet he soon finds himself falling under her charms. Iain Glen and Holliday Grainger also star. 8 p.m. HBO

Stalked by a Reality Star A teenager lies about her age to get into a Hollywood party, where she meets a handsome reality TV star, who soon becomes obsessed with her. Cynthia Preston, Scott William Wilson and Emily Bader star in this new TV thriller. 8 p.m. Lifetime

Churchill This 2017 World War II drama from director Jonathan Teplitzky finds Brian Cox in the title role. Miranda Richardson, John Slattery, Julian Wadham and Danny Webb also star. 8 p.m. Starz

Love, Once and Always A woman (Amanda Schull) is dismayed to learn that her childhood sweetheart (Peter Porte) plans to tear down a beloved old estate and replace it with a golf course, so she mounts a campaign to save the property no matter what in this new TV romance. 9 p.m. Hallmark